The basic function of a hydraulic lifter is to ride up and down on the cam lobe and open the valves when the cam rotates. Sounds simple doesn't it? Wrong !

The hydraulic lifter is one of the most complex components of an internal engine, with a multitude of moving parts with the main purpose of maintaining zero lash. When the camshaft is at the beginning of lift, all the lifter internal components are in the zero-lash position. The check ball is seated and has sealed the high pressure chamber. Starting valve lift cycle (where the camshaft pushes the lifter up), the valve spring applies force on the lifter, which slightly depresses the internal components. Then, a controlled leak-down occurs: An internal spring pushes the internal components firmly against the push rod to remove any lash in the system, after which the process starts all over again.

A hi strength, break in additive is now required for installation of new flat tappet lifters. Recent changes in engine oils have eliminated zinc and phosphorus from typical oils and this is absolutely necessary for new cam/lifter installations. We recommend a Competition Cams # 159 for this application.